Cover or trapdoor which is height-adjustable and relevant installation method

ABSTRACT

A kit for producing and method for positioning a cover or trapdoor which is height-adjustable includes providing a frame adapted to be mounted on a base in a manner that is telescopically slidable to a limited extent therein so to be height-adjusted with respect to the base, and at least one cover member which is detachably coupled to the frame and which is adapted to be received in an opening thereof, and providing the as a mold adapted to produce the base from reinforced concrete.

The present invention relates to a cover or trapdoor which is height-adjustable and the relevant installation method.

In the following context, the term “cover” is intended to be understood to indicate a closure device and an upper portion for a shaft which is constituted by a fixed portion (frame) and one (or more) movable portion(s) (cover member) which is intended to be positioned on collection and inspection shafts for the closure and access thereof; the trapdoor differs from the cover in that the cover member is provided with gaps which allow the discharge of runoff water. Covers and trapdoors are widely used in paved areas, such as, for example, street surfaces, squares, areas divided into lots and the like, in order to facilitate access for works below and/or to allow the discharge of the runoff water. In the following context, the reference to covers or to trapdoors is intended to include, unless otherwise indicated, both cases.

In previous patents of the same Applicant, including the application EP2084333 and the Italian Patent Application PD2011A000118, there are described covers and trapdoors which are produced so as to be able to position them correctly level with the ground and in particular so as to be repositioned at the correct level when there have to be carried out reconstruction works of the paved areas, for example, in order to re-apply asphalt or in the case of subsidence of the structure below.

Those covers have been completely satisfactory for the proposed objectives on condition that the base on which the frame is mounted is produced in a “workmanlike” manner or with all the relevant skills and in full compliance with the positioning specifications indicated by the manufacturer.

The following defects are encountered among the positioning defects which are most frequent and/or mainly damaging for the subsequent functionality of the cover.

Base construction defects. There may occur cases in which the base is not constructed with a structure which is suitable for supporting provided loads. The unified norms provide for the frame of the cover to rest on a base which is suitable for supporting loads of 125-250-400 kN and above, in accordance with the arrangement thereof. In the opposite case, there may be subsidence of the cover following breakages or deformations of the base. Another problem may be connected with a lack of or insufficient insulation between the outer side of the frame and the filling casting. In fact, that casting, in the absence of sufficient insulation from the frame of the cover, may impede the height adjustment of the frame, making it a “captive” of the cement layer and causing, for any asphalting or re-paving of the surface involved, the removal and subsequent re-positioning of the cover.

There are further other defects which may be attributed to the known covers and trapdoors, for example, when the covers are installed in new urbanized areas and are normally positioned level with the spreading of the coarse-finish asphalt layer.

Subsequently, for example, once the division into lots has been completed, it becomes necessary to lift the cover in order to take account of the subsequent final asphalting which will require a raising of the cover by approximately 4 cm. To this end, there may be provided shims which serve to level the subsequent positioning at street level. For this reason, the shims would have to be left in the shaft in order to be made available during asphalting when the frame of the cover and the relevant cover member have to be lifted again so as to be level with respect to the asphalted surface. However, it is often the case that the positioning operators forget this requirement and remove the shims so that, when the paving work has been completed, perhaps after months or years, they are for the most part irreparable.

There are further problems relating to the theft of cast iron cover members, their possible removal as a result of the effect of “apparent winds” of heavy vehicles, with a consequent risk that the frame remains open, involving extremely serious risks of incidents.

Generally, therefore, the known covers and trapdoors are subject to a number of disadvantages so as to involve at least a substantial expenditure in terms of manpower, materials as well as high technical times in order to make the paved surface suitable for traffic again. This last aspect in particular is a cause of worse danger both for road users and for operators for highway maintenance.

The main technical problem addressed by the present invention is to provide a new cover or trapdoor which is structurally and functionally configured to overcome the disadvantages set out with reference to the cited prior art.

This problem is solved by the invention by means of a cover or trapdoor which is constructed in accordance with claim 1.

The construction of the base and/or the other components of the cover such as disposable moulds which are intended to receive reinforcement rods and concrete in situ, at the location of the installer, allows a drastic reduction, on the one hand, of the production costs of the cover and the components thereof and, on the other hand, the costs of transport to the destination. In this manner, the installer can store simple moulds with which to construct the covers at the time when they are needed.

In another aspect of the invention, it is proposed to secure the shims to the frame or to the base of the cover in a non-releasable manner. This allows them to be present with certainty at times after the positioning, for example, when the asphalting of urbanized areas is carried out. In that case, the first positioning is carried out by placing the frame with simple support on the base, that is to say, approximately 4 cm below the definitive position thereof during asphalting in order then to be raised to the definitive level by inserting the shims during the asphalting.

In another embodiment of this invention, it is proposed to construct the cover members of the cover in the form of disposable moulds which are intended to be filled with reinforced cement. In this manner, there is prevented the theft of the cover members as a result of the lesser interest shown to the simple reinforced cement with respect to the more valuable iron as a result of the commercial value which is practically zero in respect of the cement-based manufactured parts. Furthermore, the cover members which are produced in this manner are heavier and therefore can be removed only with difficulty both by means of thieves and as a result of the effect of apparent wind resulting from high-speed and heavy traffic, particularly in tunnels. There is further provision for being able to lock the cover member to the frame by means of locks or the like.

Nevertheless, the low cost of reinforced concrete with respect to iron allows greater planning of requirements, thereby being able to use a greater level of dimensional standardization of the covers in favour of a lower cost of equipment and storage of the moulds alone. In effect, it is possible to produce covers in a smaller number of different dimensions, readily being able to meet greater needs with covers which are coarser but whose greater dimensions do not invalidate the cost thereof. More and more, it is possible to greatly standardize the load-bearing capacities of the cover by making them dependent only on the arrangement and number of reinforcement rods so that in this case it is also possible to use covers which are stronger and also by necessity smaller so that a single model meets the requirements which currently require the availability of different models.

Other characteristics and advantages of the invention will be better appreciated from the detailed description of an embodiment thereof which is illustrated by way of non-limiting example with reference to the appended drawings, in which:

FIG. 1 is an exploded schematic view of a cover according to the invention,

FIG. 2 is a schematic cross-section of a cover according to the invention positioned on a shaft and

FIG. 3 is an exploded schematic view of moulds for constructing the cover according to the invention.

In the Figures, there is generally designated 1 an underground shaft in which there is defined an upper surface 2 which surrounds an access opening 3. There is schematically designated 4 the ground which surrounds the shaft 1 and which is removed so as to conform to the surface 2 and which is subsequently filled preferably with gravel for positioning a cover which is generally designated 10. The shaft 1 is constructed by way of example to be square in plan but, naturally, it may assume different geometric shapes in accordance with requirements, for example, rectangular, polygonal or round, as necessary.

The cover 10 comprises a base 11 which has a geometrically coherent shape in plan with respect to that of the shaft 1; the base 11 is positioned during operation by supporting the bottom 12 thereof, which is indicated in FIG. 2, on the upper surface 2 of the shaft 1, to which it is secured by means of an application of cement mortar 50, for example, a rapidly hardening cement.

The base 11 is obtained from a mould 13, preferably of the disposable type, or is intended to form an integral part of the base 11 and to be positioned together therewith, as in the case of the embodiment illustrated in FIG. 3. It comprises a peripheral frame 14, an upper surface 15 and external side walls 16 and internal side walls 17. The internal side walls 17 define an abutment 18 which is opposite the peripheral frame 14 and which projects towards the interior of the shaft.

In an embodiment, there is formed between the internal side walls 17 and the abutment 18 a groove 19, the function of which will be explained below. The base 11 is obtained by providing at the inner side of the mould 13 reinforcement rods 20 in accordance with the types typically used for the constructions of reinforced cement and therefore introducing a cement-based mix 21 into the mould 13 provided in this manner.

There is provision for the mould 13 to be constructed for moulding with plastics material; alternatively, it can be produced from sheet steel. In any case, it is evident that there could also be provision for the use of other materials. In any case, according to a preferred embodiment, the mould 13 is not intended to be recovered after the casting has cured, being an integral part of the base.

In all cases, the mould is very light with respect to a conventional base and as such may be transported, moved and supplied at reduced cost. The storage can be carried out with an empty mould, subject to setting it up and providing the cement-based mix casting only when needed.

The cover 10 further comprises a frame 22 which has such a form as to be able to be inserted slidingly along the internal walls 17 of the base between a lowered condition in which it is supported with a bottom 23 thereof on the abutment 18 of the base 11 and a raised position in which there is removably interposed between the abutment 18 and the base 23 at least one shim 24, each shim 24 is constructed in the form of a metal strap, preferably with a thickness of 4 cm, and with a length which is a multiple of 20 and 25 cm in order to cover every possible requirement. In an embodiment, there are provided further shims 24′ with a smaller thickness, preferably of 5 mm, in order to adjust the height positioning in the event of the shaft structure giving way, as illustrated in FIG. 2. Where applicable, it is also possible to use shims with different dimensions.

The retention of the shims in the seat 18 will be maintained by the seat so as to be introduced into the depth of the cover member.

Those shims 24 are further connected to the frame 22 in a non-releasable manner by means of a cable 27. In this manner, when the frame 22 is mounted in a lowered position, that is to say, in abutment with the abutment 18, the shims 24 are left inside the shaft 1 readily accessible for the subsequent adjustment while the frame 22 has to be raised during asphalting.

The frame 22 is also preferably obtained from a mould 28, preferably of the disposable type, that is to say, which is intended to form an integral part of the frame itself and to be positioned together therewith. The mould 28 is constructed from moulded plastics material, or sheet steel, and so as to define on the frame 22 external side walls 29 and internal side walls 30. In an embodiment, the internal and/or external side walls are tapered from the bottom 23 in accordance with a cross-section which is approximately in the form of a rectangular trapezoid, in which the side perpendicular to the bottom 23 is the side which forms the external side walls 29. The base 23 is preferably extended beyond the internal side wall 30 in order to form a wing 33 which produces an abutment surface for a seal 34 (which will be discussed below). Furthermore, as may be observed in FIG. 2, the presence of the wing 33 may be considered to be optional because the tapered internal walls 30 may already per se define a receiving seat for the cover member.

The mould 28 is preferably partially filled with cement-based mix 31, for example, concrete, and reinforcement rods 32. In this manner, the portion of the mould which is directed upwards during use may be subsequently filled with a final filling layer only once the hardening of the mix 31 has taken place for the reasons which will be set out in detail below. In one embodiment, the final filling layer of the frame mould is positioned during asphalting with a layer of fine-finish asphalt. Preferably, in predefined positions of the frame 22, there are formed slot-like seats 35 which are provided to receive and retain a T-shaped head 36 of a respective pulling member 37. The pulling members 37 which are inserted with the head 36 in the respective slot-like seat 35 are then rotated by a quarter-turn so as to lock the head in the slot and to allow ready engagement for lifting the frame during adjustment of the cover in terms of height. The pulling members can be used in a lifting device 51 which is schematically illustrated in FIG. 3, or produced in order to lift the frame as described in Italian patent IT 1405059.

The cover 10 finally comprises a cover member 40 which is produced from a mould 41 and which is of moulded plastics material or sheet steel, and which is subsequently filled with a cement-based mix 42 and reinforcement rods 43. It is in any case evident that there could also be provision for using other materials.

When it is desirable to produce a trapdoor, the cover member 40 will be provided with through-slots which are not illustrated. Otherwise, the cover member 40 will be a solid structure.

The mould 41 and the resultant cover member 40 have a tapered formation in an upward direction, in the example a flattened truncated pyramid-like form with a smaller bottom 44 which is directed towards the inner side of the cover 10 and an opposite greater base 45. In this case, the filling of the mould 41 during the provision of the cover member 40 is also preferably only partial so that a layer of fine-finish asphalt 46 is superimposed on the cement-based mix 47 below. In this case, in predefined positions of the cover member 40 there are also formed slot-like seats 35 which are provided to receive a T-shaped head 36 of a respective pulling member 37. The pulling members which are inserted with the head 36 in the respective slot-like seat 35 are then rotated by a quarter-turn so as to lock the head in the slot and to allow ready engagement for lifting the cover member 40 when it is desirable to remove the frame 22 from the base 11.

In an embodiment, there is provided around the smaller base 44 a recess 48 for a seal 34.

It will be appreciated that the tapered formation of the frame 22 and the cover member 40 together with the optional presence of the seal 34 allow a particularly stable connection between the cover member 40 and the frame 22, thereby also contributing to preventing the accidental lifting of the cover member 40 in the presence of very powerful apparent winds and contributing to reducing or rather eliminating the noise of the cover as a result of the unpleasant impact effect which is typical of covers of conventional types. In an embodiment, the moulds are produced from plastics material and are connected to each other, increasing the load-bearing capacity as well as eliminating or at any rate significantly limiting the noise.

It will further be appreciated that the slot-like formation of the seats 35 allows insertion therein of a conventional cylinder for locks allowing access to the seats 35 to be locked by key and therefore prevention of the removal of the cover member 40 by acts of vandalism and the like.

Furthermore, the fact itself that the cover member 40 is produced from materials which are not suitable for recycling limits the attractiveness thereof in terms of theft remarkably.

The cover 10 described in this manner is used in the following manners.

During the establishment and urbanization of a surface to be paved, for example, by means of asphalting, there are provided for each shaft 1 to be closed a respective base 11, frame 22 and cover member 40 having suitable dimensions and formation. The base 11 is set down on the upper surface 2 of the shaft 1 and is fixed with rapidly hardening cement 50 (FIG. 2). Beforehand, there has been provision for filling the surface surrounding the shaft 1, preferably by providing a base 49 of gravel.

There is then inserted the frame 22 in direct abutment against the abutment 18 and there is carried out distribution around the base 11 of a layer of rapidly hardening cement 50.

There is then carried out the closure of the base 11 by applying a layer of coarse-finish asphalt designated 53. The frame 22 is substantially level with the road 53 at this point.

In order to carry out the subsequent asphalting, the frames 22 are lifted, the shims 24 are positioned in order to bring the free upper edge thereof into alignment with the desired road surface, the fine-finish asphalt layer 42 is distributed and it is compressed with conventional rollers.

Furthermore, when the surface has to be re-asphalted, it is simply necessary to remove the cover members 40, lower the frames 22 on the respective bases 11 by removing the shims 24 and to carry out, without any interruption, the complete milling of the existing surface in order to then position the new road surface by following the indications provided for the first asphalting.

The invention thereby solves the problem set out, achieving a number of advantages including the possibility of eliminating or in any case reducing the future costs for the height adjustment of the covers and the trapdoors in the event of periodic asphalting operations and eliminating the disruption to traffic in order to carry out those operations.

Furthermore, it allows the milling to be made simple in the event of those asphalting operations, reducing the costs for removing the worn layer in the region of the covers, eliminating the change of tooling and manual cleaning. Another advantage is afforded in that the frequent thefts of cover members and trapdoors of iron are eliminated or at any rate limited, such thefts leaving the drains dangerously uncovered. At the same time, that advantage allows the possibility of acts of vandalism to be limited, as well as the possibility of placement inside the cover of devices and explosives for terrorist purposes.

Those advantages are in fact connected with the fact that the removal of the new cover members and trapdoors will be possible only using the lifting device and will be entrusted only to those people who have the authority therefor.

Furthermore, the height and the shape of the support base of the cover on the frame advantageously ensures complete elimination of troublesome noises which may be encountered in versions in existence.

At the same time, there will be prevented damage and dangerous consequences for the traffic as have been established in cases in which cover members and trapdoors installed in the tunnels of motorways, as a result of the suction of air caused by motor vehicles of large dimensions, chassis-cab vehicles or cars passing at high speed, have been lifted from the frame, leaving the cover open.

Another advantage is also constituted by the fact that the complete provision of the kit according to the present invention with a reinforcement rod to be supplemented at the location of the installer allows standardization of the countless versions by replacing the existing covers with the new solution.

Finally, the new positioning system using the solution described above allows replacement of the existing covers, affording the advantages described with reduced and reasonable costs. 

The invention claimed is:
 1. A kit for producing a cover (10) or trapdoor which is height-adjustable, comprising: a frame (22), which is adapted to be mounted on a base (11) in a manner which is telescopically slidable to a limited extent therein, in order to be height-adjusted with respect to the base (11); and at least one cover member (40), which is detachably coupled to the frame (22) and which is adapted to be received in an opening thereof, wherein the base (11) comprises a base mold (13) adapted to house and produce said base from reinforced concrete.
 2. A kit according to claim 1, wherein the base mold (13) is of a disposable type.
 3. A kit according to claim 1, wherein the base mold (13) comprises reinforcement rods (20).
 4. A kit according to claim 1, wherein the base mold (13) comprises an abutment seat for the frame (22), and wherein the frame (22) comprises a counter-abutment which is configured to interact with the abutment seat, supporting the frame (22) in the base (11).
 5. A kit according to claim 4, further comprising at least one shim (24), which is provided for insertion between the abutment seat for the frame (22) and the counter-abutment of the frame (22) for levelling the frame (22) with respect to the base (11).
 6. A kit according to claim 5, wherein the at least one shim (24) is secured in a non-releasable manner to the base (11) or the frame (22).
 7. A kit according to claim 1, wherein one or both of the cover member (40) or the frame (22) are produced as molds (28, 41), which are configured to be filled with a cement-based mix.
 8. A kit according to claim 7, wherein one or both of the frame (22) or the cover member (40) comprise reinforcement rods (32, 43).
 9. A kit according to claim 7, wherein one or both of the mold (28, 41) of the cover member (40) or of the frame (22) is of a disposable type.
 10. A kit according to claim 1, wherein surfaces of mutual connection and coupling between the frame (22) and cover member (40) are tapered.
 11. A kit according to claim 1, wherein one of both of the frame (22) or the cover member (40) comprise slot-shaped seats (35) for lifting devices (51).
 12. A kit according to claim 11, further comprising a cylinder for locks, which is adapted to be inserted and locked in the slot-shaped seats.
 13. A kit according to claim 1, wherein the base (11) comprises a peripheral frame (14) and an abutment (18), which is opposite the peripheral frame (14) and which projects towards an inner side of a shaft, the frame (22) being in direct abutment against the abutment (18).
 14. A method for positioning a cover (10), comprising: providing a kit comprising: a frame (22), which is adapted to be mounted on a base (11) in a manner which is telescopically slidable to a limited extent therein, in order to be height-adjusted with respect to the base (11); and at least one cover member (40), which is detachably coupled to the frame (22) and which is adapted to be received in an opening thereof, wherein the base (11) comprises a base mold (13) adapted to house and produce said base from reinforced concrete; and assembling the frame with the at least one cover member and the base.
 15. A method for positioning a cover (10) according to claim 14, wherein the base (11) is placed on an upper surface (2) of a shaft (1) and is subsequently fixed with rapidly hardening cement (50).
 16. A method for positioning a cover (10) according to claim 14, wherein one or both of the mold (28, 41) of the frame (22) or the cover member (40) is initially filled only partially with a cement-based mix (31, 47).
 17. A method for positioning a cover (10) according to claim 16, further comprising a step of applying a layer of coarse-finish asphalt (53) after hardening the cement-based mix (31).
 18. A method for positioning a cover (10) according to claim 17, wherein the frame (22) is moved substantially level with the layer of coarse-finish asphalt (53). 